Molecular Detection of Leishmania in Phlebotomine Sand Flies (Diptera: Psychodidae) from a Cutaneous Leishmaniasis Focus at Xakriabá Indigenous Reserve, Brazil

Abstract

Autochthonous cases of American cutaneous leishmaniasis (ACL) have been reported since 2001 in the Xakriabá Indigenous Reserve located in the municipality of São João das Missões in northern Minas Gerais state, Brazil. In order to study the presence of Leishmania DNA in phlebotomine sand flies, six entomological collections were carried out from July 2008 through July 2009, using 40 light traps placed in peridomicile areas of 20 randomly selected houses. From October 2011 through August 2012, another six collections were carried out with 20 light traps distributed among four trails (five traps per trail) selected for a previous study of wild and synanthropic hosts of Leishmania. A total of 4,760 phlebotomine specimens were collected belonging to ten genera and twenty-three species. Single female specimens or pools with up to ten specimens of the same locality, species and date, for Leishmania detection by molecular methods. Species identification of parasites was performed with ITS1 PCR-RFLP using HaeIII enzyme and genetic sequencing for SSU rRNA target. The presence of Leishmania DNA was detected in eleven samples from peridomicile areas: Lu. longipalpis (two), Nyssomyia intermedia (four), Lu. renei (two), Lu. ischnacantha, Micropygomyia goiana and Evandromyia lenti (one pool of each specie). The presence of Leishmania DNA was detected in twelve samples from among the trails: Martinsmyia minasensis (six), Ny. intermedia (three), Mi. peresi (two) and Ev. lenti (one). The presence of Leishmania infantum DNA in Lu. longipalpis and Leishmania braziliensis DNA in Ny. intermediasupport the epidemiological importance of these species of sand flies in the cycle of visceral and cutaneous leishmaniasis, respectively. The results also found other species associated with Leishmania DNA, such as Mt. minasensis and Ev. lenti, which may participate in a wild and/or synanthropic cycle of Leishmania transmission in the studied area.

Detection of multiple circulating Leishmania species in Lutzomyia longipalpis in the city of Governador Valadares, southeastern Brazil

“…Lu. longipalpis is the main vector of L. infantum in Brazil [6], however, reports of PCR detection of other Leishmania species in this sand flies have been described in several studies [33, 38, 43, 44]. In agreement with our results, these studies described the association of Lu.…”

“…longipalpis with the parasites of Leishmania genus was 16.2%, being 13% with Leishmania subgenus and 4% with Viannia subgenus. These rates are higher than those found in other regions of Brazil [33, 38, 43, 44, 48], which may contribute to the high risk of Leishmania infection in Governador Valadares. In studies carried out in Brazil, the natural infection rate of Lu.…”

“…The gold-standard method used to study the rate of natural infection in endemic areas has been the digestive tract dissection of female sand flies, permitting the direct observation of the parasites [32]. However, this technique is laborious, timeconsuming, difficult to process a large number of samples and does not allow the identification of genus and species [32, 33]. Alternatively, molecular techniques, such as PCR, are highly specific and more sensitive, allowing the detection of a single parasite depending on the used primer [34, 35].…”

“…Alternatively, molecular techniques, such as PCR, are highly specific and more sensitive, allowing the detection of a single parasite depending on the used primer [34, 35]. The use of PCR for detection of Leishmania DNA in sand flies is a useful technique for the identification of putative vectors in different geographical areas [33, 36-39]. Some targets used to analyze the infection in sand flies are ITS1 [33, 37, 38] and kDNA [36, 40, 41].…”

“…In agreement with our results, these studies described the association of Lu. longipalpis with L. infantum, and also with L. amazonensis [43] and L. braziliensis (or a parasite belonging to Viannia subgenus) [33, 38, 43, 44]. Mixed infections of L. (Leishmania) sp.…”